Reddit mentions of Tanged Hoof Rasp 14 Inch Rasp

Look at it logically. Chefs (especially high end ones) generally don't care about what steel they use, so even though I'm guessing rasp steel isn't the greatest Chefs wouldn't mind.

BUT

Chefs DO care if their knives go dull in a few seconds, and at 800 dollars, you've got every right to be steel snobby and a 14 dollar rasp probably doesn't cut it. Also, chefs will want a handle that they can be EXTREMELY precise with (just watch Gordon Ramsay scream about how things aren't evenly cut). Sure you can grab onto the blade but most chefs are moving at 100mph and could do with 10 extra hands let alone one. And finally the rasp/"grater" part is pretty far down the blade, so if you're chopping anything thicker than an inch or so you're going to "grate" the shit out of ONE SIDE of the food, which makes it uneven, which again, watch ramsay FLIP HIS SHIT any time his food isn't the most symmetrical thing in the universe.

So while she does have some high end clients, I don't think it's worth 800 bucks (admittedly for the largest knife). It's a cool idea, but I'm pretty sure most chefs will want a seperate knife and grater.